Tsunami Forces on a Coastal Bridge Deck with a Box Girder

In this paper, the solitary wave forces on coastal bridge superstructures with box girders are discussed numerically. Although there are some empirical equations for wave forces on typical bridge superstructures, no relation has yet been proposed for predicting the tsunami-induced forces on box girder superstructures due to the lack of knowledge of wave forces on these kinds of superstructures. In this study, first, a solitary wave model was utilized to represent the tsunami. Then, the Reynolds-averaged Navier-Stokes equations combined with the shear stress transport (SST) k-omega turbulence model were utilized for the wave simulations. Additionally, the horizontal and vertical forces on the bridge superstructures were simulated, taking into account four water depths and five wave heights for each bridge elevation. The effectiveness of the numerical model was proven by a comparison with the experimental measurements. The numerical results showed that the difference in wave forces acting on T-type girders and box girders was significant. Finally, an improved empirical equation was proposed for estimating the tsunami-induced forces on box girder bridges.